const isBirthday = true
const greeting = isBirthday ? "生日快乐" : "早上好"
console.log(greeting)

const age = 15
const isAdult = age >= 18 ? "成年" : "未成年"
console.log(isAdult)

const socre = 85
console.log( socre >= 90  ? "优秀" : 
    (socre >= 60 ? "及格" : "不及格") 
)